1. Field of the Invention
The present invention relates to a transmitting apparatus for transmitting the audio data reproduced from the recording medium to the network and its control method, and a receiving apparatus for receiving the above audio data and its control method.
2. Description of the Related Art
The digital audio/video system capable of achieving the high quality-of-audio reproduction by transmitting the digital audio data or digital video data, which is reproduced by the reproducing device such as the DVD (Digital Versatile Disc) player, etc., to the network including the transmission line such as the serial bus (IEEE Std. 1394-1955 IEEE Standard for a High Performance Serial Bus) based on the IEEE 1394 standard, etc. and also receiving the audio data by the receiving apparatus such as the amplifier, etc., is being implemented.
According to such digital audio/video system, such a flow control is carried out that the audio data are stored in the buffer on the receiving apparatus side and also the reproducing speed on the transmitter side is controlled within the speed variation of ±1% not to cause the overflow or the underflow of such buffer.
According to this flow control, since the receiving apparatus can read the audio data stored in the buffer by using the clock with the quartz precision, the high quality audio output can be achieved without the jitter component.
Out of the DVD-Audio discs that are reproduced by the reproducing apparatus such as the DVD player, etc., there is the disc in which the portion (track) containing the audio only and the portion (track) containing the video and the audio are present.
When the data reproduced from such DVD-Audio disc are transmitted/received according to the above flow control, the problem is not particularly caused in reproducing the portion (track) containing the audio only.
However, in the reproduction of the portion (track) containing the video and the audio, since the reproducing clock on the reproducing device side is controlled by the receiving apparatus within the maximum variation of ±1%, there is caused the problem that the distortion of the video image may be generated. Further, there is caused the problem that, since the audio data are buffered in the receiving apparatus, the coincidence of timings between the video and the audio (so-called lip synchronization) is lost.
The present invention has been made in view of the problems mentioned above, and it is an object of the present invention to provide a transmitting apparatus and a control method therefor and a receiving apparatus and a control method therefor capable of eliminating the distortion of the video and also attaining the lip synchronization even when the portion of the DVD-Audio disc, etc., in which the video and the audio are contained, is reproduced.